Infographic: Why Not All Cell Divisions Are Equal

Phosphorylation of a protein called Sara found on the surface of endosomes appears to be a key regulator of asymmetric splitting in fruit flies.

Aug 31, 2017

Shawna Williams

THE SCIENTIST STAFFDuring cell division in fruit flies’ sensory organ precursor cells, microtubules draw endosomes with the Sara protein on their surface to the central spindle. There, Sara is phosphorylated, causing the endosomes to detach from the spindle and travel to one side of the mother cell, with most of them moving into the daughter cell known as pIIa, where microtubule disassembly is greater. That cell divides again to form the outer shaft and socket of a hair on the fly’s back, while its sibling, pIIb, gives rise to the hair’s inner sheath and neuron. Without Sara, hair formation is compromised.